net.sf.saxon.expr.instruct

## Class BlockIterator

- java.lang.Object
- - net.sf.saxon.expr.instruct.BlockIterator

- All Implemented Interfaces:
    SequenceIterator<Item>

      public class BlockIterator
      extends Object
      implements SequenceIterator<Item>

  Iterate over the instructions in the Block, concatenating the result of each instruction into a single combined sequence.

- - ### Field Summary

    - ### Fields inherited from interface net.sf.saxon.om.SequenceIterator

      `GROUNDED, LAST_POSITION_FINDER, LOOKAHEAD`

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `BlockIterator(Expression[] children, XPathContext context)`

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `close()` Close the iterator.
    `Item` | `current()` Get the current value in the sequence (the one returned by the most recent call on next()).
    `BlockIterator` | `getAnother()` Get another SequenceIterator that iterates over the same items as the original, but which is repositioned at the start of the sequence.
    `int` | `getProperties()` Get properties of this iterator, as a bit-significant integer.
    `Item` | `next()` Get the next item in the sequence.
    `int` | `position()` Get the current position.

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### Constructor Detail

    - #### BlockIterator

          public BlockIterator(Expression[] children,
                       XPathContext context)

  - ### Method Detail

    - #### next

          public Item next()
                    throws XPathException

      Get the next item in the sequence.
      Specified by:
        `next` in interface `SequenceIterator<Item>`
      Returns:
        the next item, or null if there are no more items.
      Throws:
        `XPathException` - if an error occurs retrieving the next item

    - #### current

          public Item current()

      Get the current value in the sequence (the one returned by the most recent call on next()). This will be null before the first call of next().
      Specified by:
        `current` in interface `SequenceIterator<Item>`
      Returns:
        the current item, the one most recently returned by a call on next(); or null, if next() has not been called, or if the end of the sequence has been reached.

    - #### position

          public int position()

      Get the current position. This will be zero before the first call on next(), otherwise it will be the number of times that next() has been called.
      Specified by:
        `position` in interface `SequenceIterator<Item>`
      Returns:
        the current position, the position of the item returned by the most recent call of next()

    - #### close

          public void close()

      Description copied from interface: `SequenceIterator`
      Close the iterator. This indicates to the supplier of the data that the client does not require any more items to be delivered by the iterator. This may enable the supplier to release resources. After calling close(), no further calls on the iterator should be made; if further calls are made, the effect of such calls is undefined.

      (Currently, closing an iterator is important only when the data is being "pushed" in another thread. Closing the iterator terminates that thread and means that it needs to do no additional work. Indeed, failing to close the iterator may cause the push thread to hang waiting for the buffer to be emptied.)

      Specified by:
        `close` in interface `SequenceIterator<Item>`

    - #### getAnother

          public BlockIterator getAnother()
                                   throws XPathException

      Get another SequenceIterator that iterates over the same items as the original, but which is repositioned at the start of the sequence.
      Specified by:
        `getAnother` in interface `SequenceIterator<Item>`
      Returns:
        a SequenceIterator that iterates over the same items, positioned before the first item
      Throws:
        `XPathException` - if any error occurs

    - #### getProperties

          public int getProperties()

      Get properties of this iterator, as a bit-significant integer.
      Specified by:
        `getProperties` in interface `SequenceIterator<Item>`
      Returns:
        the properties of this iterator. This will be some combination of properties such as `SequenceIterator.GROUNDED`, `SequenceIterator.LAST_POSITION_FINDER`, and `SequenceIterator.LOOKAHEAD`. It is always acceptable to return the value zero, indicating that there are no known special properties. It is acceptable for the properties of the iterator to change depending on its state.

Copyright (c) 2004-2013 Saxonica Limited. All rights reserved.